Vergara and Manganiello attend the premiere of "Magic Mike XXL" on June 25 in Hollywood, Calif.

(Kevin Winter/Getty Images)

Instead, according to an invitation obtained by Hello! Magazine, the couple has asked their reported 400 guests to donate to charities such as St. Jude's Children's Hospital, for which Vergara serves as a celebrity ambassador.

The wedding festivities are set to kick off with a cocktail party Saturday, followed by the couple exchanging vows at 6 p.m. on Sunday.